Some 4,000 people gathered in Tahrir Square in the centre of the town, some 270 kilometres (173 miles) north of Baghdad, after Friday Muslim prayers.

Witnesses told AFP some of the crowd began throwing stones at police, who responded with batons.

An official at the emergency room at Sulaimaniyah hospital said 16 policemen and two civilians were among those admitted.

The two injured civilians were a protester and a journalist working for a media outlet linked to Iraqi President Jalal Talabani's Patriotic Union of Kurdistan (PUK), witnesses said.

Sulaimaniyah has since February 17 been the scene of near-daily demonstrations by thousands of people criticising the stranglehold on the region's politics of the two main Kurdish parties: the PUK and Massud Barzani's Kurdistan Democratic Party (KDP).

The protesters also denounced corruption and called for the prosecution of those responsible for the deaths of three young protesters killed in clashes with security forces and KDP guards in February.